Stator and rotary electric machine having phase windings wound in multiple double slots

ABSTRACT

In a stator having a stator core and phase windings, slots are formed in the stator core and each slot accommodates conductors in a layer structure from one end to the other end of the slot in a radial direction of the stator core. The phase windings in one phase have conductors accommodated in a first slot and a second slot which are adjacently formed in the stator core. An electrical connection between the conductors in a n-th layer and the conductors in a (n+1)-th layer includes that the conductors accommodated in the first slot are electrically connected together, the conductors accommodated in the second slot are electrically connected together, and the conductors accommodated in the first slot are electrically connected with the conductors accommodated in the second slot. This connection eliminates a phase difference in the first slot and the second slot in a distributed winding structure.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to and claims priority from Japanese PatentApplication No. 2012-245299 filed on Nov. 7, 2012, the contents of whichare hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to stators and rotary electric machinescomprised of a stator which is composed of a stator core and a pluralityof phase windings.

2. Description of the Related Art

There is a conventional technique which discloses a stator of a rotaryelectric machine having a simple structure capable of decreasing eddycurrent loss generated by leakage flux without increasing amanufacturing cost. For example, Japanese patent laid open publicationNo. JP 2012-130093 has disclosed a conventional technique regarding arotary electric machine having the above function. In the structure ofthe conventional rotary electric machine disclosed in JP 2012-130093,the stator is comprised of segment conductors and a plurality of dividedphase windings. The segment conductors are divided into N segmentgroups. Phase windings are composed of divided N segment groupsconnected in parallel. The divided N segment groups are arranged inparallel.

The patent document JP 2012-130093 shows the technique in which twophase windings are arranged in parallel. However, the patent document JP2012-130093 does not show a measure of suppressing a generation of acirculating current when the number of the phase windings arranged inparallel is more than two. In other words, it cannot always prevent acirculating current from being generated when the technique disclosed inthe patent document JP 2012-130093 is applied to a rotary electricmachine having a stator comprised of a plurality of phase windings ofmore than two, i.e. multiple phase windings arranged in parallel.

SUMMARY

It is therefore desired to provide a stator and a rotary electricmachine equipped with the stator capable of suppressing generation of acirculating current when phase windings are wound in parallel inmultiple double slots, i.e. several pairs of slots in a distributedwinding structure.

An exemplary embodiment provides a stator having an improved structure.The stator is comprised of a stator core and a plurality of phasewindings. The stator core is comprised of a plurality of slots formedand arranged in the stator core in a circumferential direction of thestator core. Each of the phase windings is comprised of conductors. Theconductors are electrically connected together to form the phasewindings. The conductors are accommodated in the corresponding slots sothat the conductors are stacked in a plurality of layers in each of theslots from one side to the other side in a radial direction of thestator core. Each of the phase windings is comprises the conductorsconnected together and accommodated in a first slot and a second slot.The first slot and the second slot are adjacent to each other. That is,each of the phase windings is wound around the stator by electricallyconnecting the conductors which are accommodated in a (2n−1)-th layer inthe first slot to the conductors accommodated in a 2n-th layer in thesecond slot. The electrical connection between the conductors in then-th layer and the conductors in the (n+1)-th layer is such that (a) theconductors accommodated in the first slot are electrically connectedtogether, (b) the conductors accommodated in the second slot areelectrically connected together, and (c) the conductors accommodated inthe first slot are electrically connected with the conductorsaccommodated in the second slot.

In the structure of the stator previously described, the phase windingis wound around the stator by electrically connecting the conductorsaccommodated in the first slot and the second slot. In addition to thestructure in which the conductors accommodated in the same slot areelectrically connected, the conductors, which are accommodated indifferent slots such as the first slot and the second slot, areelectrically connected. This connection structure of the conductors cansuppress a circulating current from flowing in the phase windingsarranged in parallel in the first slot and the second slot in adistributed winding (which correspond to double slots contained inseveral pairs of slots). This makes it possible to prevent loss causedby a circulating current.

In accordance with another aspect of an exemplary embodiment, there isprovided a stator in which each of the phase windings has a terminal.The terminals are electrically connected to form a connection selectedfrom a star connection, a delta connection and a star-delta connection.This structure makes it possible to suppress generation of a circulatingcurrent and avoids any loss caused by the generation of a circulatingcurrent even if the phase windings are formed in a connection selectedfrom the star connection, the delta connection and the star-deltaconnection.

In accordance with another aspect of an exemplary embodiment, there isprovided a rotary electric machine comprised of the stator having thestructure previously described and a rotor arranged to face the stator.This makes it possible to suppress an electric potential differencebetween phases and to easily select a phase connection selected from astar connection, a delta connection and a star-delta connection.

It is possible to electrically connect a plurality of conductors havinga predetermined shape (for example, a character “U” shape) together, andalso acceptable to use a single wiring having the same length as theconductors would be when connected together.

A layer connecting conductor (which will be explained in a firstexemplary embodiment) has a crank shape and connects the conductor in a2n-th layer to a conductor in a (2n+1)-th layer. It is possible for thelayer connecting conductors to be made of any material and have anyshape so long as it can connect the conductors, i.e. the phase windingstogether. It is possible to apply the concept of the stator according tothe present invention to a rotary electric machine so long as it has arotary section (for example, a rotary axis, a rotary shaft, etc.). Inother words, it is possible to apply the concept of the stator tovarious types of electric machine such as an alternator, an electricmotor, and a motor generator.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred, non-limiting embodiment of the present invention will bedescribed by way of example with reference to the accompanying drawings,in which:

FIG. 1 is a view showing a schematic cross section of a structure of arotary electric machine having a stator according to a first exemplaryembodiment of the present invention;

FIG. 2 is a plan view showing a structure of the stator in the rotaryelectric machine according to the first exemplary embodiment of thepresent invention;

FIG. 3 is a view showing a detailed structure of a part of the stator inthe rotary electric machine according to the first exemplary embodimentof the present invention;

FIG. 4 is a perspective view showing a conductor accommodated in a slotformed in a stator core of the stator in the rotary electric machineaccording to the first exemplary embodiment of the present invention;

FIG. 5 is a view showing a cross section of the conductor to be insertedand accommodated in a corresponding slot of the stator in the rotaryelectric machine according to the first exemplary embodiment of thepresent invention;

FIG. 6 is a view showing a structure of a layer connecting conductor 16d to connect conductors in the (2n+1)-th layer and 2n-th layer in a slotin the stator of the rotary electric machine according to the firstexemplary embodiment of the present invention;

FIG. 7 is a view showing a schematic structure of windings 161 and 162which are wound in two layer groups such as first and second layers, andthird and fourth layers in a slot of the stator of the rotary electricmachine according to the first exemplary embodiment of the presentinvention;

FIG. 8 is a view showing a schematic structure of a part of a wavewinding (or a series winding) in which conductors are connected togetherto form U, V and W phase windings in the rotary electric machineaccording to the first exemplary embodiment of the present invention;

FIG. 9 is a perspective view showing a part of the turn sections of thewindings forming the phase winding in the stator of the rotary electricmachine according to the first exemplary embodiment of the presentinvention;

FIG. 10 is a plan view showing a relationship between teeth, slots andconductors in the stator of the rotary electric machine according to thefirst exemplary embodiment of the present invention;

FIG. 11 is a view showing a cross section of the conductors along theXI-XI Line shown in FIG. 9;

FIG. 12 is a view showing a schematic circuit structure of a firstconnection example of the conductors in which the conductors are dividedinto two parallel connections arranged in parallel;

FIG. 13 is a plan view showing a phase connection in which theconductors are arranged in the double slots (the multiplier number S ofslots is two (S=2)) in the stator of the rotary electric machineaccording to the first exemplary embodiment of the present invention;

FIG. 14 is a plan view which schematically shows a relationship betweena series circuit section and the conductors accommodated in the slots inthe stator of the rotary electric machine according to the firstexemplary embodiment of the present invention;

FIG. 15 is a schematic view showing a first wire connection structure (astar connection) of the phase windings in the stator of the rotaryelectric machine according to the first exemplary embodiment of thepresent invention;

FIG. 16 is a schematic view showing a second wire connection structure(or a delta connection) of the phase windings in the stator of therotary electric machine according to the first exemplary embodiment ofthe present invention;

FIG. 17 is a schematic view showing a third wire connection structure (astar delta composite connection) of the phase windings in the stator ofthe rotary electric machine according to the first exemplary embodimentof the present invention;

FIG. 18 is a plan view showing a schematic structure of a wireconnection part of the phase windings of the stator of the rotaryelectric machine according to the first exemplary embodiment of thepresent invention;

FIG. 19 is a schematic view of a first structure of rearranging the wireconnection of the phase windings of the stator by a rearranging section1B in the rotary electric machine according to the first exemplaryembodiment of the present invention;

FIG. 20 is a view showing a schematic circuit structure of a secondconnection example of the conductors in which the conductors are dividedinto two parallel connections arranged in parallel in the rotaryelectric machine according to a second exemplary embodiment of thepresent invention;

FIG. 21 is a plan view which schematically shows a relationship betweena series circuit section and the conductors accommodated in the slots ofthe stator of the rotary electric machine according to the secondexemplary embodiment of the present invention;

FIG. 22 is a schematic view showing a fourth wire connection structure(a star connection) of the phase windings of the stator of the rotaryelectric machine according to the second exemplary embodiment of thepresent invention;

FIG. 23 is a view showing a schematic circuit structure of a thirdconnection example of the conductors in which the conductors are dividedinto two parallel connections arranged in parallel in the rotaryelectric machine according to a third exemplary embodiment of thepresent invention;

FIG. 24 is a plan view which schematically shows a relationship betweena series circuit section and the conductors accommodated in the slots ofthe stator of the rotary electric machine according to the thirdexemplary embodiment of the present invention;

FIG. 25 is a schematic view showing a fifth wire connection structure (astar connection) of the phase windings of the stator of the rotaryelectric machine according to the third exemplary embodiment of thepresent invention;

FIG. 26 is a view showing a schematic circuit structure of a connectionexample of the conductors in which the conductors are divided into fourparallel connections arranged in parallel in the rotary electric machineaccording to a fourth exemplary embodiment of the present invention;

FIG. 27 is a plan view which schematically shows a relationship betweena series circuit section and the conductors accommodated in the slots ofthe stator of the rotary electric machine according to the fourthexemplary embodiment of the present invention;

FIG. 28 is a schematic view showing a sixth wire connection structure (astar connection) of the phase windings of the stator of the rotaryelectric machine according to the fourth exemplary embodiment of thepresent invention; and

FIG. 29 is a schematic view of a second structure of rearranging thewire connection of the phase windings of the stator by a rearrangingsection 1B in the rotary electric machine as a modification of the firstto fourth exemplary embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, various embodiments of the present invention will bedescribed with reference to the accompanying drawings. In the followingdescription of the various embodiments, like reference characters ornumerals designate like or equivalent component parts throughout theseveral diagrams.

First Exemplary Embodiment

A description will be given of a stator 12 and a rotary electric machine10 equipped with the stator 12 according to a first exemplary embodimentwith reference to FIG. 1 to FIG. 19.

FIG. 1 is a view showing a schematic cross section of a structure of therotary electric machine according to the first exemplary embodiment. Therotary electric machine 10 shown in FIG. 1 is comprised of the stator12, a rotor 13, a rotary shaft 20, and a casing member 11. The stator12, the rotor 13 and the rotary shaft 20 are accommodated in the casingmember 11. The rotary electric machine 10 is electrically connected to apower conversion device 30 through input and output cables 17, etc. Thecasing member 11 of the rotary electric machine 10 is independentlyprepared and fixed to a casing member of the power conversion device 30by a fixing member, or they are assembled together. The casing member ofthe power conversion device 30 will be explained later.

For example, there are, as the fixing members, bolts and nuts, malescrews and female screws, through holes and split pins, welding,caulking, etc. It is also possible to combine not less than two selectedfrom these fixing members. It is also possible to use extended portionsof the conductors 16 as the input and output cables 17. The conductors16 will be explained in detail later.

The rotary shaft 20 is rotatably supported by the casing member 11through a bearing 15, etc. The rotary shaft 20 is fixed to a centralsection of the rotor 13 by the fixing member or the rotary shaft 20 andthe rotor 13 are assembled together. The rotary shaft 20 and the rotor13 rotate together.

FIG. 2 is a plan view showing a structure of the stator 12 in the rotaryelectric machine 10 according to the first exemplary embodiment. Thestator 12 has a stator core 12 a. FIG. 3 is a view showing a detailedstructure of a part of the stator 12 in the rotary electric machine 10according to the first exemplary embodiment.

As shown in FIG. 2 and FIG. 3, the stator 12 formed in a cylindricalshape is arranged at a radially outer surface side of the rotor 13. Aplurality of slots 12 b is formed in the stator core 12 a along acircumferential direction of the stator core 12 a. The stator 12 isfixed to the casing member 11 (see FIG. 1) by the fixing members. Theinterval between the adjacent slots 12 b can be adjusted. However, fromthe standpoint of having a uniform magnetic flux flow and increasing anoutput torque of the rotary electric machine 10, it is preferable toform the slots 12 b in the stator core 12 a at a regular interval alongthe circumferential direction of the rotor 11. As shown in FIG. 3, theslot 12 b is formed between the adjacent teeth 12 c.

In the structure of the stator 12 shown in FIG. 2, the multiplier numberS of the slots 12 b is two, the number Mn of the magnetic poles iseight, and the number p of the phases is three. Therefore the number Snof the slots 12 b is expressed by the following equation:Sn=S×Mn×p=2×8×3=48,where S indicates the multiplier number of slots and is a positiveinteger, Mn indicates the number of magnetic poles and is a positiveinteger, and p indicates the number of phases and is a positive integer.

The conductors 16 are accommodated in the slots 12 b. The conductors 16form the phase windings of the stator 12. For example, as shown in FIG.3, the four conductors 16 are accommodated in each slot 12 b so that thefour conductors 16 are aligned in a radial direction of the stator core12 a of the stator 12. It is possible to arrange a plurality of theconductors 16 in each slot 12 b. In the first exemplary embodiment, eachslot 12 b is divided into four layers such as a first layer, a secondlayer, a third layer and a fourth layer. The first layer, the secondlayer, the third layer and the fourth layer are arranged in each slot 12b from an inner diameter side to the outer diameter side of the stator12.

A part of each of the conductors 16 which is accommodated in thecorresponding slot 12 b will be referred to as the “accommodated section19 of the conductor 16.

FIG. 8 is a view showing a schematic structure of the conductors 16arranged in a wave winding (or a series winding) in which the conductors16 are connected in series to form the phase winding in the rotaryelectric machine 10 according to the first exemplary embodiment. Asection in the conductor 16, which is exposed and projected from theinside of the slot 12 b will be referred to the “turn section 14”. Theentire of the turn section 14 is called to as the “coil end” of thestator 12. A part of the turn section 14 is used as lead wires. Forexample, as shown in FIG. 1, the lead wire is electrically connected tothe power conversion device 30.

A description will now be given of the structure of the conductors 16with reference to FIG. 4 and FIG. 5.

FIG. 4 is a perspective view showing the conductor 16 accommodated inthe slot 12 a of the stator 12 in the rotary electric machine 10according to the first exemplary embodiment. FIG. 5 is a view showing across section of the conductor 16 accommodated in the slot 12 a of thestator 12 in the rotary electric machine 10 according to the firstexemplary embodiment.

As shown in FIG. 4, the conductor 16 has a character “U” shape. That is,the conductor 16 is comprised of the turn section 14, the accommodatedsection 19 and an end section 16 t. The turn section 14 has a stairshaped section 14 s comprised of a plurality of stair shaped parts. Onestair shaped part in the stair shaped section 14 s has a height H whichcan be adjusted to a desired height for various applications. It ispossible to easily stack the conductors 16 in an axial direction of thestator 12 when the height H of one stair shaped part in the stair shapedsection 14 s is formed approximately equal to the height (or a thickness“Th”) of the conductor 16. It is possible to adjust the number of thestepped parts in the stair shaped section 14 s in the conductor 16. Forexample, it is possible to determine the number of the stair shapedparts in the stair shaped section 14 s on the basis of a gap between theadjacent accommodated sections 19 in the conductor 16.

A crank section 14 c is formed at a central part of the stair shapedsection 14 s. The crank section 14 c is obtained by bending a conductor16 in a crank shape in order to shift the conductor 16 toward a radialdirection of the stator 12. The crank section 14 c has a maximum heightmeasured from an end surface of the stator core 12 a. It is possible tooptionally bend the crank section 14 c in a radial direction of thestator 12. When the crank section 14 c is bent by a width Wd of theconductor 16, it is possible to easily shift the conductor 16 toward theradial direction of the stator 12.

It is also possible for each of the conductors 16 to have a structurewithout the stair shaped section 14 s. It is possible for the rotaryelectric machine to have the same effects so long as each of theconductors 16 has the crank section 14 c without the stair shapedsection 14 s.

FIG. 7 is a view showing a schematic structure of windings 161 and 162in U phase windings in the stator 12 of the rotary electric machine 10according to the first exemplary embodiment. The windings 161 and 162are wound in two layer groups, that is, first and second layers, andthird and fourth layers.

The end section 16 t of some conductors 16 has a terminal section T, forexample, the end sections of the windings 161 and 162 shown in FIG. 7which will be explained later. The terminal section T is designated bythe alternate long and two short dashes line shown in FIG. 4.

The end sections 16 t are connected by soldering or welding. Similarly,the end section 16 t is electrically connected to the terminal section Tby soldering or welding.

The technical term “welding” indicates fusion welding such as gaswelding, arc welding, electroslag welding, electron beam welding, laserbeam welding, etc., and pressure welding such as resistance welding,forge welding, etc.

FIG. 5 shows a cross section of the conductor 16 along the V-V lineshown in FIG. 4. The turn section 14 and the accommodated sections 19 inthe conductor 16 are covered with an insulation film 16 r for example, aresin film, etc. That is, the turn section 14 is made of a metal member16 m, for example, a copper wire, etc. and the accommodated sections 19are covered with the insulation film 16 r. On the other hand, becausethe end section 16 t in the conductor 16 is not covered with theinsulation film, the metal member 16 m in the end section 16 t isexposed to the outside and the end section 16 t is electricallyconnected to the terminal T or the end section of other conductors 16.

FIG. 6 is a view showing a structure of a layer connecting conductor 16d in the stator 12 of the rotary electric machine 10 according to thefirst exemplary embodiment. The layer connecting conductor 16 d has acrank shape and connects the 2n-th layer (for example, winding 161) tothe (2n+1)-th layer (for example, winding 162). The layer connectingconductor 16 d is disposed at a front side and another conductor 16 isdisposed at a rear side (or a back side) shown in FIG. 6. Because thelayer connecting conductor 16 d is disposed at the horizontal section Hrformed at the central section of another conductor 16, no interferenceoccurs between the layer connecting conductor 16 d and another conductor16 as shown in FIG. 6, FIG. 9, FIG. 10 and FIG. 11. The structure of theconductors shown in FIG. 9, FIG. 10 and FIG. 11 will be explained later.

FIG. 7 shows a schematic connection of the conductors 16 which belong toone phase winding, for example, U phase. The winding 161 is formed bysequentially connecting the conductors 16 in the first layer and thesecond layer. One end section of the phase winding 161 is electricallyconnected to a terminal T1, and the other end section of the phasewinding 161 is electrically connected to a terminal T2. The winding 162is formed by sequentially connecting the conductors 16 in the thirdlayer and the fourth layer. One end section of the winding 162 iselectrically connected to a terminal T3, and the other end section ofthe winding 162 is electrically connected to a terminal T4. Each of theterminals T1, T2, T3 and T4 corresponds to the terminal T of theconductor 16 shown in FIG. 4. The winding 161 and the phase and thewinding 162 are formed by connecting the conductors 16 in the two layerswhich are radially adjacent to each other.

Because the rotary electric machine according to the first exemplaryembodiment has three phase (for example, U phase, V phase and W phase),each of the three phases has the windings 161 and 162. It is notnecessary that each of the windings 161 and 162 is equipped with theterminal T.

FIG. 8 shows an example of connecting the windings 161 and 162 in threephases. That is, the winding 161 makes the U phase winding 16U. Thewinding 161 makes the V phase winding 16V. The winding 161 makes the Wphase winding 16W. Similarly, the winding 162 makes the U phase winding16U. The winding 162 makes the V phase winding 16V. The winding 162makes the W phase winding 16W. It is possible to determine the number ofthe windings 161 and 162 to be used in each of the three phases U, V andW.

The stator 12 shown in FIG. 8 is comprised of the U phase winding 16U,the V phase winding 16V and the W phase winding 16W. In the structure ofthe stator 12 according to the first exemplary embodiment, a pair of theslots 12 b forms each phase. Each of the conductors 16 shown in FIG. 8is designated by its number which indicates the number of thecorresponding slot in which the conductor 16 is accommodated in the Uphase winding 16U, the V phase winding 16V and the W phase winding 16W.For example, the conductor 16 indicated by the reference number 1 isinserted and accommodated in the slot 12 b having the slot number 1.

The U phase winding 16U as one of the three phase windings U, V and W iscomprised of the conductors 16 which are connected in series andaccommodated in the slots 12 b designated by the slot numbers 1, 7, 13,19, 25, 31, 37 and 43, respectively. As omitted from the drawings, the Uphase winding 16U is comprised of the conductors 16 which are connectedin series and accommodated in the slots 12 b designated by the slotnumbers 2, 8, 14, 20, 26, 32, 38 and 43, respectively. One U phasewinding 16U is electrically connected to the other U phase winding 16Uat the connection section Un.

The V phase windings 16V and the W phase windings 16W have the samestructure of the U phase windings 16U. That is, one V phase winding 16Vis comprised of the conductors 16 which are connected in series andaccommodated in the slots 12 b designated by the slot numbers 3, 9, 15,21, 27, 33, 39, and 45 respectively. Similar to the structure of the Uphase windings 16U, one V phase winding 16V is electrically connected tothe other V phase winding 16V at the connection section Vn. The W phasewinding 16W is comprised of the conductors 16 which are connected inseries and accommodated in the slots 12 b designated by the slot numbers5, 11, 17, 23, 29, 35, 41, and 47 respectively. Similar to the structureof the U phase windings 16U and 16V, one W phase winding 16W iselectrically connected to the other W phase winding 16W at theconnecting section Wn.

As previously described, the U phase windings 16U, the W phase windings16V and the W phase windings 16W are formed by winding the conductors 16in the corresponding slots 12 b.

A description will now be given of a part of the phase windings, inparticular the turn section 14 in each of the phase windings withreference to FIG. 9, FIG. 10 and FIG. 11.

FIG. 9 is a perspective view showing a part of the turn sections of thewindings forming the phase windings in the stator 12 of the rotaryelectric machine 10 according to the first exemplary embodiment. FIG. 10is a plan view showing a relationship between teeth 12 c, the slots 12b, the conductors 16 x (16) and 16 y (16) and the layer connectingconductor 16 d (16) in the stator 12 of the rotary electric machine 10according to the first exemplary embodiment. FIG. 11 is a view showing across section of the conductors 16 along the XI-XI Line shown in FIG. 9.

That is, FIG. 9, FIG. 10 and FIG. 11 shows the conductor 16 x in the 2nlayer, the conductor 16 y in the (2n+1) layer, and the turn sections 16d through which the conductor 16 x in the 2n layer is switched to theconductor 16 y in the (2n+1) layer.

FIG. 10 shows the conductor as the layer connecting conductor 16 d whichis bent in the horizontal section Hr formed at the central section ofthe conductors 16 x (16) and 16 y (16). As shown in FIG. 11, a gap “G”is formed between the layer connecting conductor 16 d, the conductor 16x and the conductor 16 y. There is therefore no interference between thelayer connecting conductor 16 d, the conductor 16 x and the conductor 16y.

Next, a description will now be given of a method of connecting thewindings 161 and 162 (the U phase winding 16U, the V phase winding 16Vand the W phase winding 16W) with reference to FIG. 12 to FIG. 17.

FIG. 12 is a view showing a schematic circuit structure of a firstconnection example of the conductors in which the conductors are dividedinto two parallel connections arranged in parallel. FIG. 13 is a planview showing a phase connection in which the conductors are arranged inthe slots when the multiplier number S of slots is two (S=2) in thestator 12 of the rotary electric machine 10 according to the firstexemplary embodiment.

In the winding connection shown in FIG. 12 to FIG. 17, two seriescircuit sections are connected in parallel per phase winding. That is,FIG. 12 to FIG. 17 show an example of a parallel connection of the twoof phase windings. The total number of the series circuit sectionsconnected in parallel is referred to as the “parallel number”. In thestator 12 according to the first exemplary embodiment, the parallelnumber is two.

The upper part in FIG. 12 shows an example of a winding connectioncomposed of windings A1, a2, B3, b4, B1, b2, A3, and a4 which areconnected in series.

As shown in FIG. 13, the winding A1 is wound, i.e. accommodated in thefirst layer of the slot A in the double slots 12 b. The winding a2 iswound, i.e. accommodated in the second layer of the slot a in the doubleslots 12 b. Further, as shown in FIG. 13, the winding B1 is wound, i.e.accommodated in the first layer of the slot B in the double slots 12 b.The winding b2 is wound, i.e. accommodated in the second layer of theslot b in the double slots 12 b. Other windings B3, b4, A3 and a4 arewound by the same structure.

The windings 161 and 162 shown in FIG. 7 are wound twice on the stator12 through the layer connection sections 16 d. The duplex windings A1-a2 are comprised of the winding A1 and the winding a2 connected by theconnection conductor A1 a 2. The duplex windings B3-b 4 are comprised ofthe winding B3 and the winding b4 connected by the connection conductorB3 b 4. The duplex windings B1-b 2 are comprised of the winding B1 andthe winding b2 connected by the connection conductor b2A3. The duplexwindings A3-a 4 are comprised of the winding A3 and the winding a4connected by the connection conductor A3 a 4. The bottom side of FIG. 12shows an example of a simplified structure of the winding connection atthe upper side of FIG. 12.

A description will now be given of various examples of the windingconnection by using the double windings which are wound around thestator 12 of the rotary electric machine 10 according to the firstexemplary embodiment.

FIG. 13 shows an example of the connection state of the layer connectionconductor through which the windings in different layers are connected.In the structure of the stator 12 having the double slot structure (i.e.the multiplier number S of the slots 12 b is two (S=2)), the one phasewinding uses adjacent two slots. Each of the U phase winding, the Vphase winding and the W phase winding is assigned to the adjacent twoslots 12 b. A group of the U phase winding, the V phase winding and theW phase winding uses every six slots 12 b. For a brief explanation, asshown in FIG. 13, a left side slot in a pair of the adjacent slots 12 bas the double slots is designated by reference character “A”, and theright side slot therein is designated by reference character “B”. Whenthe winding in one phase strides over the winding in other phase, a leftside slot in a pair of the adjacent slots 12 b as the double slots isdesignated by reference character “a”, and the right side slot thereinis designated by reference character “b”, and a left side slot in a pairof the adjacent slots 12 b is designated by reference character “α”, andthe right side slot therein is designated by reference character “β”.The slot A, the slot a and the slotα are arranged at the left side inthe corresponding pair of the slots. On the other hand, the slot B, theslot b and the slot β are arranged at the right side in thecorresponding pair of the slots as the double slots. In other words, theslot A, the slot a and the slot α are the same side in the pair of theadjacent slots as the double slots (A=a=α). Similarly, the slot B, theslot b and the slot β are on the same side in the pair of the adjacentslots as the double slots (B=b=β). In addition, although an actualstator has an arc shape or a circular shape, FIG. 13 shows that thestator 12 has a rectangle shape for brief explanation.

As shown in FIG. 13, the connection conductor A1 a 2 connects theconductor A1 accommodated in the first layer in the slot A with theconductor a2 in the second layer in the slot a. Similarly, theconnection conductor B1 b 2 connects the conductor B1 accommodated inthe first layer in the slot B with the conductor b2 in the second layerin the slot b. The connection conductor A2 b 3 connects the conductor A2accommodated in the second layer in the slot A with the conductor b3 inthe third layer in the slot b. The connection conductor B2 a 3 connectsthe conductor B2 accommodated in the second layer in the slot B with theconductor a3 in the third layer in the slot a.

The connection conductor A3 a 4 connects the conductor A3 accommodatedin the third layer in the slot A with the conductor a4 in the fourthlayer in the slot a. The connection conductor B3 b 4 connects theconductor B3 accommodated in the third layer in the slot B with theconductor b4 in the fourth layer in the slot b. It is also acceptable touse the layer connecting conductor 16 d as one or more of theseconnection conductors A1 a 2, B1 b 2, A2 b 3, B2 a 3, A3 a 4 and B3 b 4.

As understood from the examples of the winding connection shown in FIG.12 and FIG. 13, it is possible to show the winding connection by usingthe pair of the slot A and the slot B shown in FIG. 14.

FIG. 14 is a plan view which schematically shows a relationship betweenthe series circuit section and the conductors accommodated in the slotsA and B of the stator 12 of the rotary electric machine 10 according tothe first exemplary embodiment.

The series circuit C11 designated by the alternate long and short dashline in the bottom part of FIG. 12 is made by the series connectioncomposed of the winding A1, the connection conductor A1 a 2, the windinga2, the connection conductor a2B3, the winding B3, the connectionconductor B3 b 4, and the winding b4. Similarly, the series circuitsection C12 designated by the alternate long and short dash line in thebottom part of FIG. 12 is made by the series connection composed of thewinding B1, the connection conductor B1 b 2, the winding b2, theconnection conductor b2A3, the winding A3, the connection conductor A3 a4, and the winding a4. The conductors 16 (i.e. the winding 161 and thewinding 162) are connected in n layers (n=4 in the first exemplaryembodiment) to make the connection in each of the series circuitsections C11 and C12,

According to the first exemplary embodiment as previously described, theseries circuit C11 and the series circuit C12 are composed of the samenumber of the conductors in the slot 12 b designated by the referencecharacter “A” at the left side and the slot 12 b designated by thereference character “B” at the left side in the pair of the adjacentslots. The connection conductor a2B3 in the series circuit C11 and theconnection conductor b2A3 in the series circuit C12 connect theconductors in the different slots. The windings accommodated in the pairof the slots A and B which are adjacently arranged have in general adifferent electric potential. However, as shown in FIG. 14, because thelayer connection shown in FIG. 14 makes it possible to eliminate such adifferent electric potential, it is possible to prevent a circulatingcurrent from being generated in the series circuit as a closed circuitshown in FIG. 12, and to prevent loss caused by the circulating current.

When the connection example of one phase winding shown in FIG. 12, FIG.13 and FIG. 14 is applied to the three phase windings shown in FIG. 15,FIG. 16 and FIG. 17, each of the windings shown in FIG. 15, FIG. 16 andFIG. 17 are connected in parallel. The same connection is designated bythe same reference character.

FIG. 15 is a schematic view showing a first wire connection structure asa star (Y) connection composed of the U phase winding 16U, the V phaseconnection 16V and the W phase winding 16W in the stator 12 of therotary electric machine 10 according to the first exemplary embodiment.

FIG. 16 is a schematic view showing a second wire connection structure(or a delta (Δ) connection) composed of the U phase winding 16U, the Vphase connection 16V and the W phase winding 16W in the stator 12 of therotary electric machine 10 according to the first exemplary embodiment.FIG. 17 is a schematic view showing a third wire connection structurecomposed of the star connection shown in FIG. 15 and the deltaconnection shown in FIG. 16 as a Y-delta (Δ) composite connection in thestator 12 of the rotary electric machine 10 according to the firstexemplary embodiment.

It is possible to use the end part of the windings 161 and 162 or theterminals T (T1, T2, T3 and T4), or the input and output cables 17 shownin FIG. 1 as the terminals Tu, Tv and Tw shown in FIG. 15, FIG. 16 andFIG. 17.

When the end sections of the windings 161 and 162, the terminals Tu, Tvand Tw as the terminal T, and the input and output cables 17 arearranged at a concentrated area in the stator 12, it is possible toeasily connect them together.

FIG. 18 is a plan view showing a schematic structure of a wireconnection part of the phase windings in the stator 12 of the rotaryelectric machine 10 according to the first exemplary embodiment.

As shown in FIG. 18, the bonding section 1A is formed at a concentratedarea of the stator 12. The bonding section 1A occupies an area, withinone round of the stator 12, i.e. having an angle θ (0°<θ<360°) in thestator 12. It is possible to use a terminal block as the bonding section1A.

FIG. 15, FIG. 16 and FIG. 17 show an example of the winding connection.However, it is possible to combine the star connection, the deltaconnection and a combination of the star connection and the deltaconnection according to various applications. The structure shown inFIG. 19 uses the rearranging section 1B with which the connection isswitched on the basis of a rearranging signal SW transmitted from thepower conversion device 30. The power conversion device 30 alsotransmits an electric power conversion signal Es in addition to therearranging signal SW.

The rearranging section 1B is realized by using a relay device (whichcontains a semiconductor relay). The U phase winding circuit U1, U2, theY phase winding circuits V1, V2 and the W phase winding circuits W1 andW2 are electrically connected to the rearranging section 1B.Specifically, the connection sections Un, Vn and Wn in each of the phasewinding circuits are electrically connected to the rearranging section1B.

FIG. 19 is a schematic view of the first structure of rearranging thewire connection of the phase windings of the stator 12 by therearranging section 1B in the rotary electric machine 10 according tothe first exemplary embodiment.

FIG. 19 shows the twelve connection nodes Un, Vn and Wn (i.e. U1, U2,V1, V2, W1 and W2) which are used for the three phase windings in theslots A and B shown in FIG. 13. Because there are slots a and b, andslots I and J in addition to the slots A and B used by the three phasewindings, it is necessary to use thirty two connection sections. It isalso possible to use the connection conductors A1 a 2, A2 b 3, B2 a 3,A3 a 4 and B3 b 4 as the connection sections to be connected to therearranging section 1B. The rearranging section 1B receives therearranging signal SW transmitted from the power conversion device 30,and selects one of the star connection, the delta connection, andstar-delta connection of the phase windings on the basis of the receivedrearranging signal SW.

For example, the structure having the rearranging section 1B shown inFIG. 19 can select the optimum connection according to variousapplications, for example, when a vehicle speed is low and the vehicleneeds a large torque, or when a vehicle speed is high and it issufficient for the vehicle to have a low torque.

A description will now be given of the rotary electric machine accordingto the first exemplary embodiment having the above structure previouslydescribed.

As shown in FIG. 1, when receiving the electric power conversion signalEs transmitted from the power conversion device 30, the stator 12 isexcited. When the stator 12 is excited, a rotary torque is generated byexciting the stator 12 and the rotary 13 rotates thereby. In this case,the rotary electric machine 10 acts as an electric motor. It is possibleto output the generated torque generated in the rotary electric machine10 to rotary devices such as vehicle wheels and propellers through therotor 13. It is also acceptable to arrange a power transmissionmechanism between the rotor 13 and the rotary devices (not shown). Forexample, the power transmission mechanism is one or more of a rotaryshaft, a cam, a rack and a pinion, a gear, etc.

On the other hand, because the rotor 13 rotates by a rotary power of therotary device when the power conversion device 30 outputs no electricpower conversion signal Es and the rotary device generates the rotarypower (which contains a motive power), a counter electromotive force isgenerated in the stator 12 (specifically, generated in the windings 161and 162). The generated counter electromotive force (a regenerativeforce) can be charged to a battery (omitted from the drawings) throughthe power conversion device 30. In this case, the rotary electricmachine 10 acts as an electric power generator or alternator.

By the way, even if the rotary device generates a rotary power, when thepower conversion device 30 transmits the electric power conversionsignal Es, the stator 12 generates a rotary torque and the rotor 13outputs the generated rotary torque to the rotary device. This makes itpossible to assist and promote the rotary motion of the rotary device.In this case, the rotary electric machine 10 acts as the electric motor.

A description will now be given of the effects of the rotary electricmachine according to the first exemplary embodiment having the structurepreviously described.

(1) The stator 12 is comprised of the stator core 12 a and the windings161 and 162 of plural phase parts. The slots 12 b are formed andarranged in the stator core 12 a along a circumferential direction ofthe stator core 12 a. Each slot 12 b has plural layers. For example, inthe structure of the rotary electric machine according to the firstexemplary embodiment, the windings 161 and 162 form the three phasewindings. The slots 12 b are formed and arranged in the stator core 12 aalong a circumferential direction of the stator core 12 a. Each slot 12b has the four layer parts, i.e. the first to fourth layer. Theconductors 16 are accommodated in the first to fourth layers in eachslot 12 b. The first to fourth layers are formed from the inner diameterside to the outer diameter side of each slot 12 b in the stator core 12a.

The windings 161 and 162 of one phase (for example, one of the U, V andW phases) are comprised of the conductors 16 which are accommodated inthe first slots (as the slots A, a and a which are one of a pair of theadjacent slots 12 b which are adjacently arranged in the stator core 12a) and the conductors 16 which are accommodated in the second slots (asthe slots B, b and 13 which are one of a pair of the adjacent slots 12 bwhich are adjacently arranged in the stator core 12 a). Further, thewindings 161 and 162 are wound around the stator 12 by connecting theconductors in the (2n−1)-th layer and the 2n-th layer accommodated inthe first slots and the second slots.

In this structure, as shown in FIG. 1, FIG. 3, FIG. 7, FIG. 12 to FIG.17, the conductors 16 accommodated in the n-th layer and the conductors16 accommodated in the (n+1)-th layer are connected by connecting theconductors 16 together accommodated in the first slots (i.e. connectingthe connection conductors A1 a 2 and A3 a 4 together shown in FIG. 12)and by connecting the conductors 16 together accommodated in the secondslots (i.e. connecting the connection conductors B1 b 2 and B3 b 4together shown in FIG. 12), and by connecting the conductors 16 togetheraccommodated in the first and second slots (i.e. connecting theconnection conductors a1B2 and b2A3 together shown in FIG. 12).

Because this structure makes it possible to eliminate an electricalphase difference by the windings arranged in parallel in the first andsecond slots in a distributed winding structure, that is, by the closedcircuit composed of the series circuit sections C11 and C12 which areconnected in parallel, as shown in FIG. 12), it is possible to avoidgeneration of a circulating current and loss caused by the circulatingcurrent.

(2) The rotary electric machine according to the first exemplaryembodiment has the structure in which the windings 161 and 162 areelectrically connected in parallel and the number of the conductors 16accommodated in the first slots is equal to the number of the conductors16 accommodated in the second slots, as shown in FIG. 14.

This structure makes it possible to surely cancel and eliminate anelectrical phase difference because the number of the conductors 16 isthe same in the first slots and the second slots. It is thereforepossible to reliably avoid any generation of a circulating current inthe closed circuits and loss caused by the circulating current.

(3) The rotary electric machine according to the first exemplaryembodiment has the structure in which the crank section 14 c is formedat the central section of the stair shaped section 14 s in the conductor16 shown in FIG. 4. The crank section 14 c is bent into a crank shape inorder to shift the conductor 16 toward a radial direction of the stator12. The crank section 14 c has a maximum height measured from the endsurface of the stator core 12 a. This structure makes it possible tocross the turn sections 14 of a stair shape to each other, and thewindings 161 and 162 are arrange around the stator 12 by using the n-thlayer and the (n+1)-th layer in the slots.(4) The rotary electric machine according to the first exemplaryembodiment has the structure in which the windings 161 and 162 areelectrically connected together in one of a star connection, a deltaconnection and a star-delta connection, as shown in FIG. 12 to FIG. 17.This structure makes it possible to generate an electric potentialdifference in the series circuit sections C11 and C12, and to avoidgeneration of a circulating current, and to suppress an electricpotential difference between the series circuit sections C11 and C12.(5) In the structure of the rotary electric machine according to thefirst exemplary embodiment, the bonding section 1A is formed within anangle θ (which is within a range of 0°<θ<360°) in the stator 12, asshown in FIG. 18. This structure makes it possible to easily connect thewindings 161 and 162 because the bonding section 1A is formed at theconcentrated area designated by the reference character θ in the stator12 shown in FIG. 18.(6) The stator 12 of the rotary electric machine according to the firstexemplary embodiment has the thirty-two connection sections Un, Vn andWn of the windings 161 and 162, as shown in FIG. 19. This structuremakes it possible to easily switch the connection state selected fromthe star connection, the delta connection and the star-delta connection.(7) The rotary electric machine according to the first exemplaryembodiment has the rearranging section 1B with which one of the starconnection, the delta connection and the star-delta connection isselected as shown in FIG. 19. This structure makes it possible to selectone of the star connection, the delta connection and the star-deltaconnection on the basis of the rearranging signal SW when therearranging section 1B receives the rearranging signal SW transmittedfrom the power conversion device 30. It is therefore possible to selectthe optimum winding connection according to various applications, forexample when a vehicle speed is low and the vehicle needs a largetorque, or when a vehicle speed is high and the vehicle does not need alarge torque, and it is sufficient to have a low torque.(8) The conductor 16 has the crank section 14 c which is bent into acrank shape in order to shift the conductor 16 toward a radial directionof the stator 12, as shown in FIG. 4. This structure makes it possibleto easily shift a plurality of the conductors 16 toward the radialdirection of the stator 12.(9) The conductor 16 is composed of the metal member 16 m and theinsulation film 16 r as shown in FIG. 5. The metal member 16 m iscovered with the insulation film 16 r. Because it is not necessary thateach of the conductors 16 is covered with an insulation member, theconductors 16 are easily accommodated in the slots 12 b.(10) The rotary electric machine 10 according to the first exemplaryembodiment is comprised of the stator 12, the rotor 13 which isrotatably arranged to face the stator 12, as shown in FIG. 1. Thisstructure makes it possible to suppress generation of a circulatingcurrent even if the windings 161 and 162 are connected in pluralparallel connection.

Second Exemplary Embodiment

A description will be given of the rotary electric machine according toa second exemplary embodiment with reference to FIG. 20, FIG. 21 andFIG. 22. The rotary electric machine according to the second exemplaryembodiment has basically the same structure of that of the firstexemplary embodiment. The connection structure of the windings and theconnection conductors is different between the second exemplaryembodiment and the first exemplary embodiment.

In the following explanation, the same components between the secondexemplary embodiment and the first exemplary embodiment will be referredwith the same reference numbers and characters.

In the rotary electric machine according to the second exemplaryembodiment, the number of the windings which form each of the seriescircuit sections C21 and C22 is different from the number of thewindings which form each of the series circuit sections in the firstexemplary embodiment.

FIG. 20 is a view showing a schematic circuit structure of a secondconnection example of the conductors in which the conductors are dividedinto two parallel connections arranged in parallel in the rotaryelectric machine according to the second exemplary embodiment. Theconnection example shown in FIG. 20 is different from that shown in FIG.12.

FIG. 21 is a plan view which schematically shows a relationship betweenthe series circuit section and the conductors accommodated in the slotsof the stator of the rotary electric machine according to the secondexemplary embodiment. The connection example shown in FIG. 21 isdifferent from that shown in FIG. 14. FIG. 22 is a schematic viewshowing a fourth wire connection structure (as a star (Y) connection) ofthe phase windings of the stator of the rotary electric machineaccording to the second exemplary embodiment. The connection exampleshown in FIG. 22 is different from that shown in FIG. 15.

The series circuit section C21 shown in FIG. 20 is composed of theduplex windings A1-a 2, the duplex windings B3-b 4, the duplex windingsB1-b 2 and the duplex windings A3-a 4 which are connected in series.That is, the duplex windings A1-a 2, the duplex windings B3-b 4, theduplex windings B1-b 2 and the duplex windings A3-a 4 are connectedthrough the connection conductor a2B3, the connection conductor b4B1,and the connection conductor b2A3. Similarly, the series circuit sectionC22 is composed of the duplex windings a1-α2, the duplex windings b3-β4,the duplex windings b1-β2 and the duplex windings a3-α4 which areconnected in series. The duplex windings a1-α2, the duplex windingsb3-β4, the duplex windings b1-β2 and the duplex windings a3-α4 areconnected through the connection conductor α2 b 3, the connectionconductor β4 b 1, and the connection conductor β2 a 3.

As shown in FIG. 13, the connection conductor a1α2, the connectionconductor b1β2, the connection conductor a2β3, the connection conductorb2α3, the connection conductor b3β4, and the connection conductor a3α4are shifted by six slots from the connection conductor A1 a 2, theconnection conductor B1 b 2, the connection conductor A2 b 3, theconnection conductor B2 a 3, the connection conductor A3 a 4, and theconnection conductor B3 b 4, respectively.

On the basis of the connection structures shown in FIG. 20 and FIG. 13,it is possible to show the connection structure between the slot A, theslot B, the slot a and the slot b.

The series circuit section designated by the alternate long and shortdash line in the upper part of FIG. 20 is made by the series connectionshown in FIG. 21, which is composed of the winding A1, the connectionconductor A1 a 2, the winding a2, the connection conductor a2B3, thewinding B3, the connection conductor B3 b 4, the winding b4, theconnection conductor b4 b 1, the winding B1, the connection conductor B1b 2, the winding b2, the connection conductor b2A3, the winding A3, theconnection conductor A3 a 4, and the winding a4.

Similarly to the connection structure of the series circuit section C21,the series circuit section C22 designated by the alternate long andshort dash line in the bottom part of FIG. 20 is composed of thewindings in the slots a and b, and the connection conductors.

According to the connection examples previously described, the slots aand the slots b in the series circuit sections C21 and C22 accommodatethe same number of the conductors, respectively. That is, the connectionconductors a2B3 and b2A3 in the series circuit section C21 connect theconductors accommodated in different slots. Similarly, the connectionconductors α2 b 3 and β2 a 3 in the series circuit section C22 connectthe conductors accommodated in different slots.

Similar to the structure of the rotary electric machine according to thefirst exemplary embodiment, the connection structure of the windings andthe conductors according to the second exemplary embodiment makes itpossible to surely cancel and eliminate an electrical phase differencebetween the adjacent slots, it is possible to reliably avoid anygeneration of a circulating current in the closed circuits and losscaused by the circulating current. Because the connection structure caneliminate such an electrical phase difference, it is possible for theclosed circuit shown in FIG. 20 to have a high efficiency.

FIG. 20 and FIG. 21 show an example of one phase winding connection. Itis possible to apply the connection example shown in FIG. 20 and FIG. 21to a three phase star connection example. Similar to the structure ofthe first exemplary embodiment, the windings and the connectionconductors shown in FIG. 20 and FIG. 21 are connected in parallel. FIG.22 shows an example of a three-phase star connection. Examples of adelta connection and a star-delta connection are omitted from thedrawings. It is possible to make a delta connection and a star-deltaconnection on the basis of the connection example shown in FIG. 22,similar to the connection example shown in FIG. 15, the example of thedelta connection shown in FIG. 16 and the example of the star-deltaconnection shown in FIG. 17.

Because the number of the windings to be used for forming the seriescircuit sections C21 and C22 is different between the first exemplaryembodiment and the second exemplary embodiment, it is therefore possiblefor the rotary electric machine according to the second exemplaryembodiment to have the same action and effects of the rotary electricmachine according to the first exemplary embodiment.

Third Exemplary Embodiment

A description will be given of the rotary electric machine according toa third exemplary embodiment with reference to FIG. 23, FIG. 24 and FIG.25. The rotary electric machine according to the third exemplaryembodiment has basically the same structure of that of the firstexemplary embodiment. The connection structure of the windings and theconnection conductors according to the third exemplary embodiment isdifferent from the connection structure of the first and secondexemplary embodiments.

In the following explanation, the same components between the thirdexemplary embodiment and the first exemplary embodiment will be referredby the same reference numbers and characters.

The connection structure or path of the third exemplary embodiment isdifferent from that of the second exemplary embodiment, and also thefirst exemplary embodiment.

In the connection structure of the second exemplary embodiment aspreviously described, the windings in each of the series circuitsections C21 and C22 are connected together by using two slots.

On the other hand, in the connection structure of the third exemplaryembodiment, the windings in each of the series circuit sections C31 andC32 are connected together by using four slots.

FIG. 23 is a view showing a schematic circuit structure of a thirdconnection example of the conductors in which the conductors are dividedinto two parallel connections arranged in parallel in the rotaryelectric machine according to the third exemplary embodiment.

FIG. 24 is a plan view which schematically shows a relationship betweena series circuit section and the conductors accommodated in the slots ofthe stator of the rotary electric machine according to the thirdexemplary embodiment. FIG. 25 is a schematic view showing a fifth wireconnection structure (a star (Y) connection) of the phase windings ofthe stator of the rotary electric machine according to the thirdexemplary embodiment.

FIG. 23 shows the connection example which corresponds to the connectionexample shown in FIG. 12 and the connection example shown in FIG. 20.FIG. 24 shows the connection example which corresponds to the connectionexample shown in FIG. 14 and the connection example shown in FIG. 21.FIG. 25 shows the connection example which corresponds to the connectionexample shown in FIG. 15 and the connection example shown in FIG. 22.

The series circuit section C31 shown in FIG. 23 is composed of theduplex windings A1-a 2, the duplex windings B3-b 4 and the duplexwindings b1-β2, and the duplex windings a3-α4 which are connected inseries. The duplex windings A1-a 2 is connected to the duplex windingsB3-b 4 through the connection conductor a2B3. The duplex windings B3-b 4is connected to the duplex windings b1-β2 through the connectionconductor b4 b 1. The duplex windings b1-β2 is connected to the duplexwindings a3-α4 through the connection conductor β2A3.

Similarly, the series circuit section C32 shown in FIG. 23 is composedof the duplex windings a1-α2, the duplex windings b3-β4 and the duplexwindings B1-b 2, and the duplex windings A3-a 4 which are connected inseries. The duplex windings a1-α2 are connected to the duplex windingsb3-β4 through the connection conductor α2 b 3. The duplex windings b3-β4are connected to the duplex windings B1-b 2 through the connectionconductor β4 b 1. The duplex windings B1-b 2 are connected to the duplexwindings A3-a 4 through the connection conductor b2A3.

On the basis of the connection structures shown in FIG. 22 and FIG. 13,it is possible to show the connection structure between the slot A, theslot B, the slot a and the slot b shown in FIG. 24.

The series circuit section C31 designated by the alternate long andshort dash line in the upper part of FIG. 23 is made by the seriesconnection shown in FIG. 24, which is composed of the winding A1, theconnection conductor A1 a 2, the winding a2, the connection conductor A2b 3, the winding B3, the connection conductor B3 b 4, the winding b4,the connection conductor b4 b 1, the winding b1, the connectionconductor b1β2, the winding β2, the connection conductor β2 a 3, thewinding a3, the connection conductor a3 a 4, and the winding a4.

Similarly to the connection structure of the series circuit section C31,the series circuit section C32 designated by the alternate long andshort dash line in the bottom part of FIG. 23 is made by the seriesconnection shown in FIG. 24, which is composed of the winding a1, theconnection conductor a1α2, the winding α2, the connection conductor α2 b3, the winding b3, the connection conductor b3β4, the winding β4, theconnection conductor β4B1, the winding B1, the connection conductor B1 b2, the winding b2, the connection conductor b2A3, the winding A3, theconnection conductor A3 a 4, and the winding a4.

According to the connection examples previously described, the slots A,the slots a, the slots B and the slots b in the series circuit sectionsC31 and C32 accommodate the same number of the conductors, respectively.That is, the connection conductors a2B3 and β2 a 3 in the series circuitsection C31 connect the conductors accommodated in different slots.Similarly, the connection conductors α2 b 3 and b2A3 in the seriescircuit section C32 connect the conductors accommodated in differentslots.

Similar to the structure of the rotary electric machine according to thefirst exemplary embodiment, the connection structure of the windings andthe conductors according to the third exemplary embodiment makes itpossible to reliably cancel and eliminate an electrical phase differencebetween the adjacent slots, it is possible to reliably avoid anygeneration of a circulating current in the closed circuits and losscaused by the circulating current. Because the connection structure caneliminate such an electrical phase difference, it is possible for theclosed circuit shown in FIG. 23 to have a high efficiency.

FIG. 23 and FIG. 24 show an example of one phase winding connection, aspreviously described. It is possible to apply the connection exampleshown in FIG. 23 and FIG. 24 to a three phase star connection example.Similar to the structure of the first exemplary embodiment, the windingsand the connection conductors shown in FIG. 23 and FIG. 24 are connectedin parallel. FIG. 25 shows an example of a three-phase star connection.Examples of a delta connection and a star-delta connection are omittedfrom the drawings. It is possible to make a delta connection and astar-delta connection on the basis of the connection example shown inFIG. 25, similar to the connection example shown in FIG. 15, the exampleof the delta connection shown in FIG. 16 and the example of thestar-delta connection shown in FIG. 17.

Because the third exemplary embodiment is different in connection pathof the windings from the first and second exemplary embodiments, it ispossible for the rotary electric machine according to the thirdexemplary embodiment to have the same action and effects of the rotaryelectric machine according to the first and second exemplaryembodiments.

Fourth Exemplary Embodiment

A description will be given of the rotary electric machine according toa fourth exemplary embodiment with reference to FIG. 26, FIG. 27 andFIG. 28.

The rotary electric machine according to the fourth exemplary embodimenthas basically the same structure of that of the first exemplaryembodiment. The connection structure of the windings and the connectionconductors according to the fourth exemplary embodiment is differentfrom the connection structure of the first, second and third exemplaryembodiments.

In the following explanation, the same components between the fourthexemplary embodiment and the first exemplary embodiment will be referredby the same reference numbers and characters.

The fourth exemplary embodiment is different in the number of parallelconnections from the first exemplary embodiment.

The first exemplary embodiment has disclosed the two parallelconnections. On the other hand, the fourth exemplary embodiment showsthe four parallel connections.

FIG. 26 is a view showing a schematic circuit structure of theconnection example of the conductors in which the conductors are dividedinto four parallel connections arranged in parallel in the stator of therotary electric machine according to a fourth exemplary embodiment. FIG.27 is a plan view which schematically shows a relationship between aseries circuit section and the conductors accommodated in the slots ofthe stator of the rotary electric machine according to the fourthexemplary embodiment. FIG. 28 is a schematic view showing a sixth wireconnection structure (a star (Y) connection) of the phase windings ofthe stator of the rotary electric machine according to the fourthexemplary embodiment.

For example, FIG. 26 shows the four parallel connection example whichcorresponds to the two parallel connection example shown in FIG. 12.FIG. 27 shows the connection example which corresponds to the connectionexample shown in FIG. 14. FIG. 28 shows a four parallel star connectionexample which corresponds to the two parallel star connection exampleshown in FIG. 15.

The series circuit section C41 shown in FIG. 26 is composed of theduplex windings A1-a 2 and the duplex windings B3-b 4 which areconnected in series. The duplex windings A1-a 2 are connected to theduplex windings B3-b 4 through the connection conductor a2B3. The seriescircuit section C42 shown in FIG. 26 is composed of the duplex windingsB1-b 2 and the duplex windings A3-a 4. The duplex windings B1-b 2 areconnected to the duplex windings A3-a 4 through the connection conductorb2A3. The series circuit section C43 shown in FIG. 26 is composed of theduplex windings a1-α2 and the duplex windings b3-β4. The duplex windingsa1-α2 are connected to the duplex windings b3-β4 through the connectionconductor α2 b 3. The series circuit section C44 shown in FIG. 26 iscomposed of the duplex windings b1-β2 and the duplex windings a2-α4which are connected in series. The duplex windings b1-β2 are connectedto the duplex windings a2-α4 through the connection conductor β2 a 3.

On the basis of the connection structures shown in FIG. 26 and FIG. 13,it is possible to show the connection structure between the slot A, theslot B, the slot a and the slot b shown in FIG. 27.

The series circuit sections C41 and C42 shown in FIG. 26 have the sameconnection structure of the series circuit sections C11 and C12 shown inFIG. 14.

The series circuit section C43 designated by the alternate long andshort dash line shown in FIG. 26 is made by the series connection shownin FIG. 27, which is composed of the winding a1, the connectionconductor a1α2, the winding α2, the connection conductor α2 b 3, thewinding b3, the connection conductor b3β4, and the winding β4.

On the other hand, the series circuit section C44 designated by thealternate long and short dash line shown in FIG. 26 is made by theseries connection shown in FIG. 27, which is composed of the winding b1,the connection conductor b1β2, the winding β2, the connection conductorβ2 a 3, the winding a3, the connection conductor a3α4, and the windingα4.

FIG. 26 and FIG. 27 show an example of one phase winding connection, aspreviously described. It is possible to apply the connection exampleshown in FIG. 26 and FIG. 27 to a three phase star connection example.Similar to the structure of the first, second and third exemplaryembodiments, the windings and the connection conductors shown in FIG. 26and FIG. 27 are connected in parallel. FIG. 28 shows an example of athree-phase star connection. Examples of a delta connection and astar-delta connection are omitted from the drawings. It is possible tomake a delta connection and a star-delta connection on the basis of theconnection example shown in FIG. 28, similar to the connection exampleshown in FIG. 15, the example of the delta connection shown in FIG. 16and the example of the star-delta connection shown in FIG. 17.

Because the number of the windings connected in parallel is differentbetween the fourth exemplary embodiment and the first exemplaryembodiment, it is possible for the rotary electric machine according tothe fourth exemplary embodiment to have the same action and effects ofthe rotary electric machine according to the first exemplary embodiment.

(Other Modifications)

The concept of the stator and the rotary electric machine according tothe present invention is limited by the first to fourth exemplaryembodiment previously described. It is possible for the presentinvention to have the following modifications.

The first to fourth exemplary embodiments have disclosed the structuresshown in FIG. 19 in which the two connection nodes Un in each of the Uphase winding circuits U1 and U2 are connected to the rearrangingsection 1B, the two connection nodes Vn in each of the V phase windingcircuits V1 and V2 are connected to the rearranging section 1B, and thetwo connection nodes Wn in each of the W phase winding circuits W1 andW2 are connected to the rearranging section 1B.

FIG. 29 is a schematic view of a second structure of rearranging thewire connection of the phase windings of the stator by the rearrangingsection 1B in the rotary electric machine as a modification of the firstto fourth exemplary embodiments.

As shown in FIG. 29, it is possible to have the connection structure inwhich the four connection nodes Un in each of the U phase windings U1and U2, the V phase windings V1 and V2, and the W phase windings W1 andW2 are connected to the rearranging section 1B. That is, in theconnection structure shown in FIG. 29, the connection node Un betweenthe duplex windings A1-a 2 and the duplex windings B3-b 4, theconnection node Un between the duplex windings B1-b 2 and the duplexwindings A3-a 4, the two connection nodes in the V phase windings (notshown) and the two connection nodes in the W phase windings (not shown)are added to the connection structure shown in FIG. 19. That is, theconnection node of the windings between the (2n+1)-th layer and the2n-th layer are connected to the rearranging section 1B. This structuremakes it possible to form the one-way windings arranged along an insidediameter direction in a star connection, and the other-way windingsarranged along an outside diameter direction in a delta connection.Because the number of the turns of the windings is easily adjusted, itis possible to easily select the rotation speed and the torquecharacteristics of the rotary electric machine 10.

In the structure of the first to fourth exemplary embodiments previouslydescribed, the star connection and the delta connection having the samenumber of the windings are combined to make the star-delta connection,for example shown in FIG. 17 and FIG. 30. However, the concept of thepresent invention is not limited by this. It is possible to form thestar-delta connection by using the star connection and the deltaconnection having a different number of the windings. For example, it ispossible to form a star-delta connection comprised of a star connectionhaving the windings arranged in two parallel connections and a deltaconnection having the windings arranged in four parallel connections.Similarly, it is possible to form the star-delta connection comprised ofa star connection having the windings arranged in four parallelconnections and a delta connection having the windings arranged in twoparallel connections. It is possible to adjust the number of windingsarranged in parallel to form another type connection. In particular, itis possible that the rearranging section 1B shown in FIG. 19 selects oneof the star-delta connection in which one star connection and the deltaconnection have the same number of windings arranged in parallel and theother star-delta connection having a different number of the windingsarranged in parallel. This makes it possible to easily and preciselyadjust the rotation speed and the torque characteristics of the rotaryelectric machine 10.

The first to fourth exemplary embodiments have disclosed the rotaryelectric machine in which the stator 12 has the double slot structurecomposed of the twelve slots 12 b and the multiplier number S of theslots 12 b is two (S=2). However, the concept of the present inventionis not limited by this structure. It is possible for the stator 12 tohave a multiple number S of not less than 3 (S≧3).

In the connection structure shown in FIG. 13, a pair of the two slots 12b is assigned to each of the U phase windings, the V phase windings andthe W phase windings. It is also possible to assign each of the U phasewindings, the V phase windings and the W phase windings to the slotswith another multiplier number S. In these modifications, because themultiplier number S is changed only, it is possible for thesemodifications to have the same action and effects of the first to fourthexemplary embodiments.

The first to fourth exemplary embodiments have disclosed the rotaryelectric machine in which the winding 161 is composed of the conductors16 connected in series from the first layer and the second layer, thewinding 162 is composed of the conductors 16 connected in series fromthe third layer and the fourth layer, as shown in FIG. 7. Instead ofthis connection structure, when not less than five conductors 16 arearranged in each slot 12 b, it is possible to connect the conductors 16in series in the (2n−1)-th layer to the 2n-th layer in the slot 12 b,where n is not less than three. That is, the conductors 16 are connectedin series from the fifth layer and the sixth layer in the correspondingslots, and the conductors 16 are connected in series from the seventhlayer and the eighth layer in the corresponding slots, for example.

Because the layer number is changed only in these cases, and theconductors 16 are connected in series, it is possible for thesemodifications to have the same action and effects of the first to fourthexemplary embodiments.

The first to fourth exemplary embodiments have disclosed the rotaryelectric machine in which the terminal T (T1, T2, T3 and T4) isconnected to the end section 16 t of each of the windings 161 and 162every two layers, as shown in FIG. 13.

Instead of this connection structure, when not less than four conductors16 are arranged in a radial direction in each slot 12 b, it is possibleto connect the terminal T to the end section 16 t of the windings 161and 162 every 2m layer, where m is not less than two. That is, it isacceptable to connect the terminal T to the end section 16 t of thewinding 161 and 162 every four layer or six layers. Because the numberof the terminals T is changed only in these cases, it is possible forthese modifications to have the same action and effects of the first tofourth exemplary embodiments.

The first to fourth exemplary embodiments have disclosed the rotaryelectric machine in which the stator 12 is comprised of the three phasewindings 161 and 162, i.e., the U phase windings 16U, the V phasewindings 16V and the W phase windings 16W, as shown in FIG. 8 to FIG.16. However, the concept of the present invention is not limited by thisstructure. It is possible to form the stator 12 by using phase windingsother than three phase windings. For example, it is possible to form thestator by using six phase windings composed of X phase windings, Y phasewindings and Z phase windings in addition to the U phase windings, the Vphase windings, and the W phase windings. The winding connection usingthe V phase windings 16V and the W phase windings 16W will be referredto as the “UVW winding connection”. The winding connection using the Xphase windings, the Y phase windings and the Z phase windings will bereferred to as the “XYZ winding connection. It is possible to connectthe UVW winding connection and the XYZ winding connection on the basisof one of the connections shown in FIG. 14, FIG. 15 and FIG. 16.

It is necessary to excite every winding connection by the correspondingpower conversion device 30 when the UVW winding connection is notconnected to the XYZ winding connection in the stator 12. On the otherhand, when the UVW winding connection is electrically connected to theXYZ winding connection in the stator 12, the power conversion device 30can excite them simultaneously. The above case shows the six phasewinding connection. It is possible that the stator is composed ofanother phase winding connection by the manner previously described.Because the phase number is changed only in these cases, it is possiblefor these modifications to have the same action and effects of the firstto fourth exemplary embodiments.

In the structure of each of the first to fourth exemplary embodiments aspreviously described, each slot 12 b is composed of the first layer, thesecond layer, the third layer and the fourth layer which are arranged inorder from the inner diameter side to the outer diameter side, as shownin FIG. 3 and FIG. 12. Instead of this structure, it is possible thateach slot 12 b is composed of the first layer, the second layer, thethird layer and the fourth layer which are arranged in order from theouter diameter side to the inner diameter side. Because these layerstructures have the same feature to increase the layer number from oneside to the other side in each slot 12 b, it is possible for thesemodifications to have the same action and effects of the first to fourthexemplary embodiments.

In the structure of each of the first to fourth exemplary embodiments,as previously described, the concept of the present invention is appliedto the rotary electric machine 10 of an inner rotor type in which therotor 13 is arranged at the inner diameter side and the stator 12 isarranged at the outer diameter side of the rotary electric machine, asshown in FIG. 1. However, the concept of the present invention is notlimited by this. For example, it is possible to apply the concept of thepresent invention to an electric motor of an inner rotor type, and analternator of an inner rotor type. Further, it is possible to apply theconcept of the present invention to a rotary electric machine of anouter rotor type in which the rotor 13 is arranged at the outer diameterside and the stator 12 is arranged at the inner diameter side. That is,it is possible to apply the concept of the present invention to amotor-generator of an outer rotor type, an electric motor of an outerrotor type, an alternator of an outer rotor type. Because these devicesare different in the structure of the rotor, it is possible for thesemodifications to have the same action and effects of the first to fourthexemplary embodiments.

While specific embodiments of the present invention have been describedin detail, it will be appreciated by those skilled in the art thatvarious modifications and alternatives to those details could bedeveloped in light of the overall teachings of the disclosure.Accordingly, the particular arrangements disclosed are meant to beillustrative only and not limited to the scope of the present inventionwhich is to be given the full breadth of the following claims and allequivalents thereof.

What is claimed is:
 1. A stator comprising a stator core and a pluralityof phase windings, wherein the stator core comprises a plurality ofslots formed and arranged in the stator core in a circumferentialdirection of the stator core, each of the phase windings comprisesconductors, the conductors are electrically connected together to formthe phase windings, and the conductors are accommodated in thecorresponding slots so that the conductors are stacked in a plurality oflayers in each of the slots from one side to the other side in a radialdirection of the stator core, each of the phase windings comprised ofthe conductors is accommodated in a first slot and a second slot whichare arranged adjacently to each other and is arranged around the statorcore, the conductor belonging to the (2n−1)-th layer in the first slot,wherein n is a positive integer, and the conductor belonging to the(2n)-th layer in the first slot in each of the phase windings areelectrically connected together in the radial direction of the statorcore by using first connection conductors which extend toward thecircumferential direction of the stator core, the conductor belonging tothe (2n−1)-th layer in the second slot and the conductor belonging tothe (2n)-th layer in the second slot in each of the phase windings areelectrically connected together in the radial direction of the statorcore by using second connection conductors which extend toward thecircumferential direction of the stator core, the conductor belonging tothe (2n)-th layer in the first slot and the conductor belonging to the(2n+1)-th layer in the second slot are electrically connected togetherin the radial direction of the stator core by using third connectionconductors without any intervening slots being electrically connectedbetween the (2n)-th layer in the first slot and the (2n+1)-th layer inthe second slot, a cross section of each of the first connectionconductors, the second connection conductors, and the third connectionconductors has a rectangular shape, respective end parts of the firstconnection conductors, the second connection conductors, and the thirdconnection conductors, in an axial direction of the stator core, arearranged parallel to each other, and the third connection conductor isarranged with a gap extending along the circumferential direction of thestator core so that the gap is between the third connection conductorand the conductor belonging to the (2n)-th layer in the first slot andbetween the third connection conductor and the conductor belonging tothe (2n+1)-th layer in the second slot, and the third connectionconductor is not in contact with adjacent conductors arranged in thecircumferential direction of the stator core.
 2. The stator according toclaim 1, wherein when the phase windings are arranged in parallel, thenumber of the conductors accommodated in the first slot is equal to thenumber of the conductors accommodated in the second slot.
 3. The statoraccording to claim 1, wherein the conductors have a structure in whicheach of the conductors has a stair shape and a central section of theeach of the conductors has a maximum height measured from an end surfaceof the stator core.
 4. The stator according to claim 1, wherein thephase windings are electrically connected together to form a connectionselected from a star connection, a delta connection and a star-deltaconnection.
 5. The stator according to claim 4, wherein the phasewindings are bonded at a bonding section which has an angle θ of lessthan one round of the stator.
 6. The stator according to claim 4,further comprising a rearranging section to switch the phase windings toone of the star connection, the delta connection and the star-deltaconnection.
 7. The stator according to claim 1, wherein the conductorsforming each of the phase windings are connected by connection sections,and number of the connection sections of the phase windings is thirtytwo in the stator.
 8. The stator according to claim 1, wherein each ofthe conductors has a crank section having a crank shape.
 9. The statoraccording to claim 1, wherein each of the conductors comprises a metalmember having a cross section of a rectangle shape and an insulationfilm with which the metal member is covered.
 10. A rotary electricmachine comprising: the stator according to claim 1; and a rotorarranged to face the stator.
 11. A stator comprising a stator core and aplurality of phase windings, wherein the stator core comprises aplurality of slots formed and arranged in the stator core in acircumferential direction of the stator core, each of the phase windingscomprises conductors, the conductors are electrically connected togetherto form the phase windings, and the conductors are accommodated in thecorresponding slots so that the conductors are stacked in a plurality oflayers in each of the slots from one side to the other side in a radialdirection of the stator core, each of the phase windings comprised ofthe conductors is accommodated in a first slot and a second slot whichare arranged adjacently to each other and is arranged around the statorcore, the conductor belonging to the (2n−1)-th layer in the first slot,wherein n is a positive integer, and the conductor belonging to the(2n)-th layer in the first slot in each of the phase windings areelectrically connected together in the radial direction of the statorcore by using first connection conductors which extend toward thecircumferential direction of the stator core, the conductor belonging tothe (2n−1)-th layer in the second slot and the conductor belonging tothe (2n)-th layer in the second slot in each of the phase windings areelectrically connected together in the radial direction of the statorcore by using second connection conductors which extend toward thecircumferential direction of the stator core, the conductor belonging tothe (2n)-th layer in the first slot and the conductor belonging to the(2n+1)-th layer in the second slot are electrically connected togetherin the radial direction of the stator core by using third connectionconductors without any intervening slots being electrically connectedbetween the (2n)-th layer in the first slot and the (2n+1)-th layer inthe second slot.
 12. The stator according to claim 11, wherein when thephase windings are arranged in parallel, the number of the conductorsaccommodated in the first slot is equal to the number of the conductorsaccommodated in the second slot.
 13. The stator according to claim 11,wherein the conductors have a structure in which each of the conductorshas a stair shape and a central section of the each of the conductorshas a maximum height measured from an end surface of the stator core.14. The stator according to claim 11, wherein the phase windings areelectrically connected together to form a connection selected from astar connection, a delta connection and a star-delta connection.
 15. Thestator according to claim 14, wherein the phase windings are bonded at abonding section which has an angle θ of less than one round of thestator.
 16. The stator according to claim 14, further comprising arearranging section to switch the phase windings to one of the starconnection, the delta connection and the star-delta connection.
 17. Thestator according to claim 11, wherein the conductors forming each of thephase windings are connected by connection sections, and number of theconnection sections of the phase windings is thirty two in the stator.18. The stator according to claim 11, wherein each of the conductors hasa crank section having a crank shape.
 19. The stator according to claim11, wherein each of the conductors comprises a metal member having across section of a rectangle shape and an insulation film with which themetal member is covered.
 20. A rotary electric machine comprising: thestator according to claim 11; and a rotor arranged to face the stator.